Psephenops smithi Grouvelle, 1898

Barr, Cheryl B. & Shepard, William D., 2024, A taxonomic review of the genus Psephenops Grouvelle of the Lesser Antilles with description of new species Psephenops trini, and reassignment of Peruvian species Psephenus robacki Spangler (Coleoptera: Psephenidae: Psepheninae), Insecta Mundi 2024 (45), pp. 1-22 : 5-11

Psephenops smithi Grouvelle, 1898

(= Xexanchorinus latus Grouvelle, 1898 , junior synonym)

( Fig. 2–8 )

Type localities. Grenada: Mt. Maitland and Chantilly Estate, St. Vincent; Lesser Antilles, West Indies.

Diagnosis. The greatly enlarged apical maxillary palpomeres of the male P. smithi have been considered diagnostic. Specifically, the apical maxillary palpomere is very long, nearly 2× as long as the width of an eye and nearly 2× longer than palpomeres 1–3; and is stout, about 3× wider than palpomeres 1–3, appearing inflated. There is another species (undescribed) with an enlarged terminal palpomere, although it not nearly as pronounced. The P.

smithi female lacks the enlarged palpomere and cannot be morphologically diagnosed with confidence. Psephenops smithi is compared in detail with P. trini new species in its diagnosis.

Historical perspective. The type series of both P. smithi ( Fig. 2–4 ) and X. latus ( Fig. 7, 8 ) were collected by H. H. Smith. Herbert Huntingdon Smith (21 January 1851 – 22 March 1919) was an American naturalist contracted by the West Indian Commission (West India Committee, K. Matsumoto, in litt.) of The Royal Society to do a biological survey of Trinidad and the Windward Islands from 1890–1895 ( Holland 1919). The specimens he collected were deposited in the British Museum of Natural History (NHMUK) and were subsequently loaned to numerous European entomologists who then described new species from the material. The Psephenops and Xexanchorinus specimens were accessioned by the British Museum as donation “99-37” [1899-37] (K. Matsumoto, in litt.).

In his generic description of Psephenops, Grouvelle (1898) included a striking diagnostic character: greatly enlarged apical maxillary palpomeres. Conversely, the maxillary palpi of Xexanchorinus were termed “filiformes” in his description of that genus. Neither the species descriptions of P. smithi nor X. latus mentions the palpi, or the highly modified tarsi which are now regarded as a key generic character in males. Grouvelle’s descriptions of P. smithi and X. latus , like many descriptions of his time, are inadequate to clearly define and separate these taxa from others subsequently described. Grouvelle listed three collection localities for his series of P. smithi and one for X. latus , but did not state the number of specimens on hand or designate specific types. The type locality of X. latus ( Grenada, Chantilly Estate) is the same as one of his P. smithi localities.

Champion (1913) briefly mentioned P. smithi , making note of its very large apical maxillary palpomere, in his paper describing a second species of Psephenops , P. grouvellei Champion.

Darlington (1936) synonymized P. smithi and X. latus , with X. latus becoming the junior synonym. He declared them different sexes of the same genus and species and noted that all of the P. smithi syntypes are males ( Darlington 1936: 69), and the X. latus are females. Also, one of the males was from the type locality of X. latus . As justification for the synonymy, he cited several sexually dimorphic characteristics of Psephenops , including tarsal differences. Surprisingly, however, he failed to note the unusual male maxillary palpi of P. smithi .

Delève (1967) provided the first illustrations of P. smithi and X. latus : line drawings of the pronota of both, and of the maxillary palpus and aedeagus of P. smithi . He examined one specimen of each species, which he believed to be from the type series, but did not mention where they were collected. He apparently disagreed with Darlington’s (1936) synonymy because he thought the pronota of the two taxa were too different to represent the same species ( Delève 1967; Bameul 2001).

Bameul (2001) described the subspecies P. smithi guadeloupensis Bameul from the island of Guadeloupe, which is approximately 455 km (283 mi.) distant from Grenada and St. Vincent. In addition to the adult, he described and illustrated the associated larva, gave a brief history of the description of psephenine larvae, and provided a brief key to separate the larvae of Psephenops and Psephenus . Bameul summarized the controversy regarding the synonymy, and considered Xexanchorinus to be poorly defined and requiring further study.

Current assessment. Two of the P. smithi specimens are from St. Vincent; the third specimen, from Grenada (Chantilly Estate), is the only known male specimen of P. smithi collected at the type locality of X. latus . The photographs are sufficient to conclude that the P. smithi series consists of males and the X. latus series are all females. As mentioned previously, the tarsal modification is a secondary sexual dimorphism present only in male Psephenops , and the enlarged apical maxillary palpomeres are a secondary sexual dimorphism currently known only in males of P. smithi . Because both sexes were collected together in Grenada, those specimens are almost certainly conspecific. Darlington’s (1936) opinion that the genera are synonymous is now widely accepted ( Lee et al. 2016). An excellent illustration of the aedeagus of P. smithi ( Fig. 6 ), drawn for Paul Spangler (USNM) by Y. Sohn (USNM) and never published, is included here to further clarify the species. The aedeagus was taken from the St. Vincent specimen shown in Fig. 5 . Delève (1967) previously illustrated the aedeagus, but his drawing is less detailed.

Lectotype and paralectotype designations. The NHMUK in London has three specimens of P. smithi , all males ( Fig. 2–4 ): one specimen has a round Type label and a determination label, “ Psephenops smithi ty. Grouv”, in Grouvelle’s handwriting ( Fig. 2b ) ; one has a round Syntype label with a determination label not in Grouvelle’s handwriting ( Fig. 3b ); the last has no type label, but has a determination label from 1973 saying “standing as P.

smithi Grouv. M.I. Russell det. 1973” ( Fig. 4b ). All three of the specimens have locality and accession labels of the same style, the localities are as stated in Grouvelle (1898), and so are considered to belong to the type series. However, Grouvelle did not designate a type in his description, nor indicate how many specimens he examined. Likewise, the NHMUK has two specimens of X. latus , both females ( Fig. 7, 8 ): one has a round Type label and a determination label, “ Xexanchorinus latus ty. Grouv”, in Grouvelle’s handwriting ( Fig. 7b ); the second specimen ( Fig. 8 ) has no type designation. These specimens have locality and accession labels of the same style, matching those of P. smithi , and the locality information is as stated in Grouvelle (1898), and so are considered to belong to the type series. As for P. smithi , no type was designated for X. latus and the number of specimens on hand was not indicated. The round type and syntype labels are not original, and date to the time of World War II when the curators identified and labeled valuable specimens to be relocated for safekeeping (K. Matsumoto, in litt.).

Grouvelle (1898) appears to have intended for the two specimens which bear the round Type labels to be primary types. Both specimens have determination labels in Grouvelle’s handwriting with “ty” in the lower left corner, Grouvelle’s shorthand for “type.” We therefore designate these specimens as lectotypes to fix the concepts of Psephenops smithi Grouvelle and Xexanchorinus latus Grouvelle. The remaining two specimens of P. smithi and the one of X. latus are designated as paralectotypes.

Apparently there were additional specimens belonging to the type series of P. smithi and X. latus whose whereabouts are unknown, including at least one specimen of P. smithi from Mt. Maitland, Grenada, as cited in the description. Delève (1967: 421) stated (translated from French): “I have been able to examine, in the Grouvelle collection [italics added by the authors for emphasis], one example of P. smithi Grouvelle and one example of Xexan. latus Grouvelle belonging, in all likelihood, to the series of syntypes seen by Grouvelle. (They also have a “type” label.).” Although Delève (1967: 420) published an illustration of the male genitalia of P. smithi , none of the three male syntypes held by the NHMUK has had genitalia extracted (K. Matsumoto, in litt.). So, it looks as if Grouvelle, whose collection is in the MNHN in Paris, may have retained specimens from the type series following his descriptions of the species. Nonetheless, a recent search through both the MNHN general collection and Grouvelle’s collection for these two specimens was unsuccessful (A. Mantilleri, in litt.). Because of the possibility that Delève borrowed and did not return the specimens after examining them, the general RBINS collection in Brussels, where Delève’s collection resides, has been searched also, but no specimens were found (W. Dekoninck, P. Limbourg, in litt.).

Type material examined, photographic. Psephenops smithi . Lectotype male (here designated). Type [circular off-white label with red border, printed] // W Indies. / 99-37. // St. Vincent, / W.I. / H. H. Smith. / 179. // Psephenops / Smithi / ty. Grouv [handwritten] // NHMUK015529283 [ Fig. 2b ] // LECTOTYPE / Psephenops smithi / Grouvelle, 1898 [red, printed label]. Paralectotype males (here designated). SYN- / TYPE [circular white label with blue border, printed] // W Indies. / 99-37. // ♂ // St. Vincent, / W.I. / H. H. Smith. / 128. // Psephenops / smithi, Grouv [handwritten] // NHMUK 015529284 [ Fig. 3b ] // PARALECTOTYPE / Psephenops smithi / Grouvelle, 1898 [yellow, printed label]; W. Indies. / 99-37. // Chantilly Est. / (Windward side) / Grenada, W. I. / H. H. Smith. / 175 // standing as / Psephenops / smithi Grouv. [handwritten] / M.I.Russell det. 1973 // NHMUK 015529285 [ Fig. 4b ] // PARALECTOTYPE / Psephenops smithi / Grouvelle, 1898 [yellow, printed label]. Xexanchorinus latus . Lectotype female (here designated). Type [circular off-white label with red border, printed] // W Indies. / 99-37. // Chantilly Est. / (Windward side) / Grenada, W. I. / H. H. Smith. / 175 // Xexanchorinus / latus / ty. Grouv [handwritten] // NHMUK 015529287 [ Fig. 7b ] // LECTOTYPE / Xexanchorinus latus Grouvelle, 1898 [red, printed label]. Paralectotype female (here designated). W. Indies. / 99-37. // Chantilly Est. / (Windward side) / Grenada, W. I. / H. H. Smith. / 175 // NHMUK 015529288 [ Fig. 8b ] // PARALECTOTYPE / Xexanchorinus latus Grouvelle,1898 [yellow, printed label]. [Note: The lectotype and paralectotype labels will be added to the specimens after publication of this article.]

Additional material examined, photographic. Psephenops smithi . ST. VINCENT, B.W.I. / Caratal River / Rocky & torrential / 250ft., 9Mar.1971 / A. D. Harrison // ♂ TAIL DONE BY Y. Sohn // PSEPHENOPS / SMITHI / GROUVELLE / det.PJSpangler // USNMENT / [code] / 01374932 [ Fig. 5d ].

Etymology. The species is named for the collector, Herbert Huntingdon Smith, an American naturalist. The name “smithi ” is a noun in the genitive case. For junior synonym Xexanchorinus , the trivial name, latus L., is an adjective, meaning “broad.” This likely refers to the wide pronotum or the body shape in general.

Distribution. Dominica (?), Grenada, Guadeloupe (subspecies P. s. guadeloupensis), Martinique (?), and St. Vincent, Lesser Antilles, West Indies ( Fig. 1 ). [Note: See Remarks; only larval specimens have been found on Dominica and Martinique].

Remarks. The Global Biodiversity Information Facility (GBIF) database lists P. smithi from Trinidad and Tobago based on records from OMNH, but we believe these represent new species P. trini . Bass (2003a, 2004a, 2007) reported P. smithi , identified by Paul Spangler (USMN), from Dominica, Grenada, and Tobago. We examined one of his male specimens from Tobago (the others were retained by Spangler) and found it to be P. trini , not P. smithi . We suspect that the specimens reported by GBIF and Bass’ (2003) Tobago specimens were misidentified because P. smithi was the only species known at that time from the Lesser Antilles. Bass’ (2007) record from Dominica is of a larval specimen, which currently is not identifiable, so it should be considered a tentative species identification. On Grenada, from where P. smithi was described, Bass (2004) observed that it seemed to be “the most widespread aquatic beetle in mountain streams of this island.” Meurgey and Ramage (2020) listed P. smithi from Guadeloupe, as did Peck (2016), but the source of the record(s) is unclear. In addition, Bameul (2001) cited a record of larvae from Martinique which are possibly P. smithi . Peck (2006, 2011) did not report any psephenids from either Dominica or Martinique.

We examined an adult male specimen from Venezuela (Districto Federal, Caracas) which was identified as P. smithi by the late Harley P. Brown of OMNH. It exhibits enlarged apical maxillary palpomeres, a diagnostic character of the species, however, the morphology of the aedeagus differs from that of P. smithi as illustrated by Delève (1967) and by Sohn ( Fig. 6 ). In addition, the apical maxillary palpomere of the types ( Fig. 2a, 3a ) and the USNM specimen ( Fig. 5c ) is nearly twice as long as the width of an eye, in contrast, that of the Venezuelan specimen is only about half that long. This specimen does not fit any current species description and it is likely an undescribed species. Psephenops smithi is reported from Venezuela on the Global Biodiversity Information Facility (GBIF) website based on the OMNH Recent Invertebrates Collection, but we have not verified these records.

Figures

Figure 1. Map of the southern West Indies: the Lesser Antilles, Barbados, Tobago, and Trinidad.

Figure 5. Psephenops smithi Grouvelle, adult male from St. Vincent. a) Dorsal habitus. b) Ventral habitus. c) Lateral habitus. d) Specimen labels. Photographs courtesy of Karolyn Darrow, USNM.

Figure 6. Psephenops smithi Grouvelle, aedeagus. a) Dorsal view. b) Lateral view. Illustrations by Y. Sohn †, courtesy of the USNM.

Figures 2–4. Psephenops smithi Grouvelle, adult males. 2) Lectotype from St. Vincent. a) Dorsal habitus. b) Specimen labels. 3) Paralectotype from St. Vincent. a) Ventral habitus with dissected maxillary and labial palpi. b) Specimen labels. 4) Paralectotype from Grenada. a) Ventral habitus. b) Specimen labels. Photographs courtesy of Keita Matsumoto, NHMUK.

Figures 7–8. Psephenops smithi Grouvelle (=Xexanchorinus latus Grouvelle, jr. syn.), adult females. 7) Lectotype from Grenada. a) Dorsal habitus. b) Specimen labels. 8) Paralectotype from Grenada. a) Ventral habitus. b) Specimen labels. Photographs courtesy of Keita Matsumoto, NHMUK.